Cores for cables for communication circuits



April 1933 I K. SCHUMANN 1,904,547

GORES FOR GABLES FOR COMMUNICATION CIRCUITS Filed Nov. 25. 1930 Patented Apr. 18, 1933 UNITED STATES" PATENT OFFICE KARL O1 POTSDAI, GERMANY, ASSIGNOB TO srnms-scnuoxna'rwmn mmaersnrs (imam:

V OF IBEBLIK-BIEHENSSTADT, GERMANY, A, GOBPORATION O3 corms roa roa cormo nca'rron cmcurrs Application. fled Bovember 25, 1980, Serial Io. 498,017, andin Germany November 88, 1989.

I have filed an application in Germany, November 23, 1929.

My invention relates to a method for manufacturin cores for cables for communica- 5 tion circuits.

In manufacturing cables for communication circuits it is, as is well known, difiicult to obtain for pairs as well as for stranding elements of higher order, uniform values of capacitance and therewith difierences of capacitances as uniform as possible. It has been found that after the stranding of the cable, particularly the operating capacitances vary quite non-uniformly. These unequal changes in the capacitance are apparently not only caused by ,the manner in which the twisting or stranding is performed but de nd to a great extent upon the diameter o the insulated cores and upon the alteration in the diameter occurring during the twisting or. stranding. To obtain equal capacitances it has already been proposed touse for building'up the cores and as spac' means, insulating paper of as uniform t 'ckness as possible and, of uniform dielectric constants, and paper string having as much as possible uniform thickness and being wound in each case with the same pitch. The result obtained was, however, surprising in that after the cablin of even such uniform material, some stran g elements would show values of capacitance,

quite difierent from theremainder of the stranding. elements. 7

According to my invention, this drawback is avoided by laying the paper cording 'on the cores not with a completely uniform pitch, as 'was hitherto painstakingly done but, on the contrary, with a pitch as irregular as possible. It was found that the changein the diameter of individual insulated cores and therewith the change in the values of their capacitance was principally caused by the paper cord of one core press ing itself into the paper cover of the neighbouring core at. the places where the paper covering is not supported by the cordm of the cores. a

n the accompanying drawing, "illustrating my invention, F1gs.1 to 5 show different length, but all the modes of winding-the paper cord onto adjacent cable cores.

The application of the paper cord may be carried out as shown for example in Fig. 1,.

may also be increased gradually to a certain limit and then decreased again gradually, as shown in Fig. 3. It is also possible, as shown in Fig. 5, to wind on one core, two cords running parallel at, for instance, a distance of 7 mm., for example with a total pitch of 14 mm., and on another core only one cord with a pitch of 7 mm. In this case the cores with 'two cords have about more paper, but as shown by experience this greater quantity of paper is of no great consequence for the value of the capacitance. In some cases the capacitance can be equalized by making the diameter of the cores with ,two cords larger than that of the cores with one cord, for example, by pasing the cores with two cords through a somewhat wider shaping die than thecores with one cord. In quads, it is advantageous to-arrange these cores so that the cores with one cord form one pair and those with twocords the-other pair of thequad.

. It is also' possible to wind the cords onto the cores of one pair of a quad, for example, with a pitch of 7 mm., and to give to the cord windings of the other pair a pitch of 8mm., so that it is impossible for neighbouring cores to press themselves into one another hfor any appreciable lpngth. Hers a -t e ter quantity o paper cor re d ui red fog tlie core having the smaller pitch may be compensated by making the diameter of these cores somewhat larger.. arranged When cores with cord windingsi in this manner are laid 'nextto one another, it is imposible for one of the cores to be pressed into the other for an appreciable cores when compressed, press themselves reciprocally into one another to about the same extent over a cable section of'approximately the same len b, so that although the capacitances wil increase to a certain degree, there will be no relative inequality in the values of the ca acitances.

claim as my invention:

1. A telephone cable having a plurality of insulated strands, each strand consisting of a core conductor, paper cord wound upon said conductor and paper tape spirally wound over the cord winding, adjacently located cord winding turns of adjacent cable strands having the same winding direction but difierent total itch.

2. A telephone cable having a plurality of insulated strands, each strand consisting of a core conductor, paper cord wound upon said conductor and paper tape spirally wound over the cord winding, adjacently located cord winding turns of adjacent cable strands having the same winding direction but different pitch, at least one of two adjacent strands having its cord winding laid with successive turns of unequal pitch.

3. A telephone cable having a plurality of insulated strands, each strand consisting of a core conductor, paper cord wound uponsaid conductor and paper tape spirally wound over the cord winding, ad acently located cord winding turns of adjacent cable strands having the same winding direction but different pitch, at least one of two adjacent strands having its cord winding laid with entirely irregular pitch.

4. A telephone cable having a plurality I of insulated strands, each strand consisting of a core conductor, paper cord. wound upon said conductor and paper tape spirally wound over the cord winding, adjacently located cord winding turns of adjacent cable strands having the same winding direction but different pitch, at least one of two adjacent strands having its cord winding laid with periodically varying pitch.

5. telephone cable having a plurality of insulated strands, each strand consisting of a core conductor, paper cord wound upon said conductor and paper tape spirally wound over the cord winding, adjacently located cord winding turns of adjacent cable strands having the same winding direction but different pitch, at least one of two adjacent strands having its cord winding laid with varyin itch between adjacent turns, which gradua ly varies over the length of the strand from a minimum pitch at least once to a maximum and back to a minimum.

6. A telephone cable having a plurality of insulated strands, each strand consisting of a core conductor, paper'cord wound upon said conductor and paper tape spirally wound over the cord winding, adjacently located cord winding turns of adjacent cable strands having the same winding direction 

